Administration of the MapR-DB is done primarily via the command line (maprcli) or with the MapR Control System (MCS). Regardless of whether the MapR-DB table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter
options. MapR-DB administration is associated with tables, columns and column families, and table regions.

The MapR Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight
client applications and the MapR cluster. This section describes considerations when upgrading the service, how to modify
configuration settings, and how to administer and manage the service.

gfsck

The gfsck (global filesystem check) command performs a consistency
check and repair operation on a volume or volume snapshot, including the following
entities:

All cross container links (for example, from file to filelets, or from table to
tablets)

The tabletmap key range

The attributes of filelets (uid/gid/mode)

This command identifies the unreachable files, directories, and tables in the volume and
moves them to /lost+found to be repaired. It also identifies and fixes any unreachable DB
inodes or dangling pointers to lost inodes.

Use the gfsck utility when local fsck repairs some containers at the highest epoch or
when some containers are lost (either when a lower epoch container was promoted as master or
when a container was permanently lost) at the highest epoch.

Warning: If there are alarms, such as DataUnavailableAlarm or
DataUnderReplicatedAlarm, do not run the gfsck command with the
-r (--repair) option. Running the
gfsck command with the -r
(--repair) option, might result in data loss. If necessary, first run
gfsck without the -r (--repair)
option and attempt to repair only after analyzing the command output.

Assumes that containers without valid copies (as reported by CLDB) can be
deleted automatically. If this option is not specified, gfsck
pauses for user input to verify that containers can be deleted. Enter yes to
delete, no to exit gfsck, or ctrl-C to quit.

cluster

Name of the cluster (default: default cluster)

rwvolume

Name of the volume (default: null)

snapshot

Name of the snapshot (default: null)

snapshotid

The snapshot ID (default: 0)

Example (Debug mode)

In debug mode, run the gfsck command on the read/write volume named
mapr.cluster.root: